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How Scientists Detect Ocean Life From a Single Bottle of Seawater and Why It Could Change Ocean Protection Forever · How To Protect The Ocean

• 0:00
  What if I told you that scientists can now detect hundreds of ocean species
• 0:04
  without ever seeing them, catching them, or even knowing where they are or where
• 0:09
  they were all from one bottle of seawater.
• 0:13
  Look, we know the oceans are huge and to monitor everything in the ocean
• 0:18
  is virtually impossible, especially as things are changing so quickly.
• 0:22
  And conservation decisions depend.
• 0:23
  They matter on what is in the ocean.
• 0:26
  That's how we look at things.
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  That's how we get to connect ocean species to use so that you can fall in love with
• 0:30
  them and you can see how cool they are.
• 0:32
  But traditional surveys that we do often miss some of these species
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  more than you actually realize.
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  Some are shy.
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  If there's a person in the water, some fish won't come out.
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  They'll hide because they're afraid of the person.
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  You don't get a true sense of what was actually there or what lives there.
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  But now we have this thing called environmental DNA, eDNA.
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  And this is where it comes in.
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  And in a recent study they show how powerful this method could be.
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  We're gonna talk about that on today's episode of the How
• 1:00
  to Protect the ocean Podcast.
• 1:02
  Let's start the show.
• 1:05
  Hey everybody.
• 1:06
  Welcome back to another exciting episode of the How to Protect the ocean Podcast.
• 1:10
  I'm your host, Andrew Lewin, Marine biologist and science communicator
• 1:13
  here to tell you what's happening with the ocean, how you can speak up for
• 1:15
  the ocean, and what you can do to live for a better ocean by taking action.
• 1:20
  And today we're gonna be talking about actually a method to collect
• 1:24
  data on species, especially fish species the actually improving what
• 1:28
  we know what's actually in the ocean.
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  We don't often get to talk about this.
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  I have talked about eDNA in the past.
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  It was a number of years ago when it was first coming out and we were first
• 1:37
  catching on to the glimpse of, Hey, you know what, we can take a sample of
• 1:40
  water and we can detect what was there.
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  How in the heck does that happen?
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  That's gonna be talked about on today's episode, but first I want to say,
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  'cause I didn't get to say it last episode, ' cause I recorded last episodes
• 1:51
  with Peter Neill before the new year.
• 1:53
  I wanna wish you a happy New Year.
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  I hope 2025 was great.
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  I hope 2026 is even better.
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  And if you had a crappy 2025, I hope 2026 is great ' cause it can only get better
• 2:02
  from here.
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  On this year.
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  Just a quick note, we are gonna be doing some crazy things, some fun things.
• 2:08
  We're gonna be putting out more podcasts on, not just episodes,
• 2:12
  but actual different shows on the Speak Up for Blue Podcast Network.
• 2:16
  So if you want to find out more of where you can get that, just
• 2:19
  go to speak up for blue.com.
• 2:21
  That's speak up for blue.com.
• 2:24
  You'll be able to find all those shows as we put them out, I mentioned one
• 2:28
  before the new year ended in 2025, I mentioned that we're gonna be putting
• 2:31
  out polar bears in flip flops.
• 2:32
  That's with my buddy Angelo Villagomez and I, we're gonna be talking to
• 2:35
  a bunch of people, have guests.
• 2:36
  It's a live podcast.
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  We'll talk about the day when we're gonna be recording, all that kind of stuff.
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  It's gonna be once a week and it's gonna be a lot of fun.
• 2:43
  You can find it live on the YouTube channel, and then of course, pretty
• 2:46
  much soon after, you'll be able to hear it on audio, but it'll
• 2:48
  be a separate podcast in itself.
• 2:50
  We're gonna talk about conservation issues, we're gonna talk
• 2:52
  about all this kind of stuff.
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  So that's coming.
• 2:54
  We got a Fisheries podcast in the works.
• 2:55
  I'm crowdfunding for a Seagrass podcast.
• 2:58
  If you want to help with that, you can go speak up for blue.com/seagrass.
• 3:02
  Listen, this is amazing.
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  I can't wait to bring this forward.
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  I can't wait to say, Hey, you know what?
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  This is gonna be an awesome year.
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  This is gonna be so much fun.
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  And the first thing we're gonna talk about is data collection.
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  'cause what is more fun than talking about data collection?
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  Especially in this one recent study that came out.
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  They talked about eDNA, environmental DNA.
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  We kind of know what DNA is, right?
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  It's like a helix.
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  Everybody has its own separate DNA except for twins and triplets and so
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  forth, but we have our own separate DNA.
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  It's unique to ourselves.
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  And then a lot of times when we think about it, I want you to
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  think of times in terms of like
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  when you leave DNA, like at a crime scene or somebody leaves DNA at a crime
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  scene and they're able to identify that that person was there or that you see
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  it in crime shows that their DNA was on the knife or the gun or whatever.
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  It's obviously a negative aspect of using DNA, but the fact is you can
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  identify people based on their DNA.
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  Well, imagine if you can do that for fish and understand that like in this piece
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  of water, they actually swam through at some point, at some time and they
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  left a piece of themselves back there.
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  Whether it's a scale, whether it's mucus, whether it's bodily
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  fluids, whether it's just poop or, or urine, it doesn't matter.
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  They actually left something there that you can pick up that has DNA
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  inside of that, and then that will detect that that fish or that species
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  was there at that particular time.
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  Now it won't identify individuals.
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  We don't know that much, but it can identify fish species to species,
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  a fish to species, but it can also do like the families and so forth.
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  And this is a really cool thing 'cause like, just imagine.
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  You don't need nets, you don't need cameras, and you don't
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  need divers to do everything or to see anything and everything.
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  Like I want you to think about when you're out in the ocean and a net goes
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  in, there are certain fish species and certain species that can actually
• 4:45
  avoid those nests pretty quickly.
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  They can swim away.
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  And so for the mammals can swim a, some of 'em get caught by
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  accident, some of them die.
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  But imagine not having to use a net if you don't need to use a net.
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  Imagine not having to use a net to detect what those species are.
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  You can use a different method like the eDNA method It's
• 4:59
  just a really cool thing.
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  When you put a camera down there, you're actually disturbing when you put nets.
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  You're disturbing the ocean.
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  When you're putting a camera down there, you're actually disturbing the ocean.
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  Probably not as much, but you're disturbing the ocean.
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  The big thing now are BRUVs.
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  It's like a video camera down underneath a baited underwater video.
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  It's a camera.
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  It's got some bait on it.
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  And then what it does, it tracks a bunch of fish, but nothing's there.
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  There's no person there.
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  It's just a video camera with a long pole that has bait at the end, and
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  then every time a fish or something or invertebrate comes and grabs it, that
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  video camera takes the video of the thing.
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  It's constantly working.
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  And then you go and you retrieve that, and then you go through hours and hours
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  and hours and hours and hours and hours of video to see what species are there.
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  So it requires somebody to do that.
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  But now just imagine that you can take a sample of water.
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  Just a little in a test tube, or if you want more sample, if you want
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  more water, you can take like a Niskin bottle if you've ever seen
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  what a Niskin bottle looks like.
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  And you can actually take that sample.
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  And then when you do the DNA analysis, you can determine
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  whether that sample is there.
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  We're gonna talk about the intricacies of that and sort of like how great
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  or how accurate those can be.
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  So here in this study, what they did is they compared eDNA sampling to traditional
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  visual surveys by people, right?
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  Visual surveys.
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  So they have a diver in the water.
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  I think it's really cool, but first before we go into that, the authors titled this
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  environmental DNA metabarcoding enriches the conventional survey of a high diverse
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  fish community in the Dongsha Atoll.
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  This is done in Taiwan.
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  This is all from people at the Department of Oceanography, the National Sun
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  Yat-sen University, Kaohsiung, Taiwan.
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  That's where they're from.
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  And it was accepted on December 3rd, so it just came out in 2025.
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  The lead author seems to be You-Chen Liu, is the name and Yi-Ching Yang.
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  There's a number of different, I'll put the authors down there too, 'cause they
• 6:41
  deserve to be acknowledged, obviously, for their work and being able to provide
• 6:45
  this out openly so that I can talk to you about it, which is kind of cool.
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  So essentially they compared eDNA sampling to visual surveys.
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  So a person in the water or people in the water doing those visual surveys.
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  The results essentially were the eDNA detected significantly more species.
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  So essentially they had divers in the water looking for species.
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  They run a transact, they run a number of transects.
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  They identify all the fish And then they finish their transact.
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  They do another one.
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  They finish their, and they go through.
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  That's expensive.
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  That takes a lot of work.
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  It's tiring, depending on the conditions, if they're visible or not You don't
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  know really what's going on if it's not visible, so you can't see as much.
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  But if it is visible and you're in a reef area, you've got a lot of clarity.
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  You can see pretty far if you're a very good diver And so forth, and you
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  have good eyesight, better eyesight than I do, and you can identify all
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  these species, but it takes time.
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  It takes a lot of money and that's not always there, right?
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  And so that could be a difficult thing to look at.
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  However, when you look at eDNA, they take a little sample, right?
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  Or they take a bunch of samples and they run the DNA for all this.
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  They identify the different strands of DNA, and then they cross-reference
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  it to a number of different databases, and they're able to identify the fish.
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  That is pretty cool.
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  Like I can't tell you how cool that is.
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  The amount of money that it saves, the amount of effort that saves.
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  Just to go in and be able to take water samples and then identify it through
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  a DNA analysis is mind boggling to me.
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  The amount of work you can do, more than what you can do if you just have
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  divers in the water is ridiculous.
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  Now, it takes away the fun of diving, and we're not gonna take away diving
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  at all, but that's what it does.
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  This is pretty cool, right?
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  It doesn't say that the divers are useless.
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  It just means that the tools are doing better.
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  We still need divers to ensure that the species that are there are there
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  and see what species are there.
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  Make sure that we can ground truth them.
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  It's like using satellite imagery.
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  When I started out, I was using satellite imagery.
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  I was doing GIS, Geographical Information Systems.
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  We learned remote sensing, right?
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  And so remote sensing is using satellite imagery but to identify specific
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  features using the wavelengths and doing a bunch of different analysis
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  to look at the wavelengths, to be able to tell which features are which.
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  But you still have to go out in the field and you have to ground truth, not only the
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  geographic locations of these, of like, whether it's lidar or actual satellite
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  imagery, but you also have to make sure that what you are identifying through like
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  a bunch of different analysis, like doing a bunch of calculations and modeling.
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  You have to make sure that you have the actual information right in front of you.
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  And that is, the thing that you're identifying, you have to go in
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  the field and you'll be like, okay, this is actually a feature.
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  It's like a stone or it's a reef, it's a coral, or whatever that might be.
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  You still have to do that.
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  You still have to go out and do that.
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  But this kind of tells you like, Hey, the DNA's there.
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  You still have to use divers to make sure that all that's
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  there, but the DNA is there.
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  You're pretty good once you know it.
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  So it fills out those blind spots that divers can't see, because of their
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  presence, which disturbs and disrupts the regular ongoings of a reef system or any
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  kind of system when you're sampling it.
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  So that's pretty cool.
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  Now, here's the thing.
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  The methods are cool but how does this really work with conservation?
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  This is a podcast we call How to Protect the ocean.
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  So, Andrew, how does this actually happen?
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  Why does this matter for ocean conservation?
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  Well, the thing is, is better data leads to better management.
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  So the more data you have, the better reasoning you have
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  for marine protected areas.
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  Managers can actually monitor changes faster and cheaper.
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  It takes a lot to take divers out in the ocean.
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  It takes a lot to take a boat for that length of time to go out.
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  But if you just have to go out and take samples of water and then come back and
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  just do DNA analysis, it's so much faster.
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  It's so much cheaper.
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  You don't need the same amount of people, all that kind of stuff.
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  And so you just get a lot more data for cheaper.
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  That's pretty cool.
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  It also tells, like, you can tell the trends, right?
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  If you have a lot of DNA at one point And then the next year you
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  don't have as many DNA, you're like, hold on a second, what's going on?
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  Are these species not in this area for a particular reason?
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  Now that we're getting a lot more species, now, I'm sure
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  that'll be the reference data.
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  And I don't know if that's the actual reference, like the best data we can
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  get ' cause it could have changed from before, but we're gonna know from
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  now on how these things are changing.
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  We'll be able to detect trends faster.
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  We'll be able to detect trends just in a better way, more accurately,
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  which will be really great.
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  It gives early warning signs of any kind of ecosystem decline.
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  Basically they become more visible because we have so many more species.
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  And I think that's really good.
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  If we don't know a species is there, we can't protect it.
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  But eDNA changes that.
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  That was a quote in the thing that I read.
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  So it was pretty cool.
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  Just think about how we have to react and how we have to manage.
• 10:59
  I always think this is interesting.
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  I worked as an environmental consultant one time, private
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  environmental consultant.
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  We worked with a lot of industries.
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  We didn't have enough data to detect, like how bats were gonna
• 11:08
  react in a specific alleyway.
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  Kinda like a wind tunnel of like a specific part in Ontario.
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  And the company's like, well, if you don't know, that's not up to us to find out.
• 11:16
  It's up to the government to find out, or academics or researchers to find out.
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  And the government's like, no, no, no, no, no.
• 11:21
  You have to pay for it to find out.
• 11:23
  It's a costly study and they did it, but they had to do
• 11:26
  it and all that kinda stuff.
• 11:27
  That happens in the ocean as well.
• 11:28
  When you don't know what a system is like, we're seeing this with deep sea mining.
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  People are like, well, if we don't know what's there, we're
• 11:33
  probably not disturbing anything.
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  Well, no, that's not true.
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  There's still out there.
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  We just don't know what's there and how it's gonna affect it.
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  We still have to know.
• 11:40
  But the fact is now with all these things going on, like climate change,
• 11:43
  overfishing, habitat loss, like I said, deep sea remote ecosystem
• 11:47
  monitoring, all that kinda stuff can be done now through eDNA.
• 11:51
  When I was a Marine technician in the Gulf of Mexico, we used to cast these
• 11:54
  CTDs, Conductivity Temperature Depth meters, conductivity, detected salinity.
• 11:58
  And we used to have this basically a data logger.
• 12:00
  And it used to be around this, ring, this like sort of outfit that
• 12:03
  goes around it, like a carousel.
• 12:05
  On the carousel it would have these Niskin bottles.
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  These are water sampling bottles that would be open.
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  We keep them open and we would be able to lower the CTD down through
• 12:14
  the water column, keep those water bottles open so water can go through
• 12:17
  it and it doesn't float and it goes all the way down to wherever
• 12:19
  you want, whatever depth you want.
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  We went from like 10 meters all the way down to 3000 meters if we were able to.
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  And then I was able to press a button on the keyboard and it
• 12:27
  would close a Niskin bottle, and it would take a sample at that depth.
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  So as long as you knew which Niskin bottle was closed, at which
• 12:34
  depth, you can go back and you can take eDNA from all those depths.
• 12:39
  Think about that.
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  Think about all the species that we can determine from there.
• 12:42
  If there's new DNA, oh, great new DNA, we don't know what it is, but we have
• 12:46
  this map of DNA of a fish that's down there, or some kind of species that's
• 12:50
  down there that we don't know what it is.
• 12:52
  It's pretty damn cool, I think.
• 12:55
  Now, of course there are limitations, like I just mentioned.
• 12:57
  The fact that we don't have the DNA of all the species.
• 13:00
  These are cross-reference, like once you get the DNA out of the
• 13:03
  water, like once you analyze it for the D, have all these DNA makeups.
• 13:06
  And then you're like, okay, cool.
• 13:07
  Now let's cross reference them into these databases.
• 13:09
  There's a number of different databases.
• 13:11
  Some are regional and more local specific.
• 13:13
  Some are massive and people just continue to grab DNA and be
• 13:17
  able to contribute to this data.
• 13:18
  So we're having more and more species available.
• 13:20
  Not just fish, but all these different species.
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  But also, we don't know, we don't have the DNA of every species,
• 13:25
  'cause we don't know every species.
• 13:27
  So eDNA tells us presence, but it also doesn't tell us population size.
• 13:30
  That's one thing, but also.
• 13:31
  We don't know the actual like DNA of everything, but it does
• 13:34
  allow us to identify what we don't know and say, Hey, you know what?
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  Here's a new species.
• 13:39
  We don't know what it is.
• 13:40
  If we ever find out, we're gonna be able to match it to that and
• 13:42
  we can find out if there's more.
• 13:43
  So it allows us to kind of bank those DNA until larger.
• 13:47
  So I think that's really great and something that we need to continue to do.
• 13:50
  But eDNA doesn't tell us the number of that population,
• 13:53
  so it tells us the presence.
• 13:54
  So great for diversity.
• 13:55
  Like species diversity, but it doesn't tell you how much of one species
• 13:58
  it is or how much of individuals are in that population size.
• 14:01
  And DNA moves with current.
• 14:02
  So it doesn't necessarily tell you that that species was there at that point.
• 14:05
  This a fish scale can go as far as a current will take it.
• 14:08
  It's not as if it can swim against, it's just a piece of skin or a
• 14:11
  piece of scale that they have.
• 14:12
  So, you know, you never know if it's gonna be there, but you
• 14:14
  know, it's around that area.
• 14:16
  And you can probably model it as we know more.
• 14:18
  And of course it works best with other methods, as I mentioned before.
• 14:21
  It's something that we look at and
• 14:23
  we have to ground truth it in the field.
• 14:25
  So that's something that's really good.
• 14:26
  But like, let's talk about what this means, right?
• 14:29
  This means we can do faster biodiversity assessments for
• 14:32
  cheaper, which is really great.
• 14:33
  We can better protect some of the overlooked ecosystems because some of
• 14:37
  those species, we don't know if they're there 'cause they hide whenever we do
• 14:39
  any other type of sampling, which is great to be able to identify those.
• 14:43
  And of course it's more inclusive science, so it's more data,
• 14:45
  more information, especially in regions with fewer resources.
• 14:48
  Imagine like island communities who cannot pay for a dive team
• 14:52
  to go down and get this safely.
• 14:55
  I had a conversation with somebody on the Beyond Jaws podcast, which
• 14:58
  will come out soon, probably out just probably when you get this podcast.
• 15:01
  But it was kind of cool because she was talking about how she
• 15:03
  went out diving and there wasn't necessarily safety divers there.
• 15:06
  Because they didn't have the money to pay for all that.
• 15:09
  So when she just went through, she's like, I probably wouldn't be able to do that
• 15:12
  now because there's needs of safety divers and other divers to help you out in medics
• 15:16
  and so forth to make sure it's safe.
• 15:18
  That's all expensive.
• 15:19
  You can't do an expensive PhD sometimes if you don't have the funding.
• 15:22
  And so to be able to have this ability to sample this size is really, really great.
• 15:26
  The science helps decision makers before it's too late.
• 15:29
  Not after an ecosystem collapses.
• 15:31
  So it's before that, which is great.
• 15:32
  So the thing is like if you want better ocean protection,
• 15:35
  it starts with the knowledge.
• 15:37
  It starts with the information.
• 15:38
  Science like eDNA helps us understand what's worth protecting,
• 15:42
  why we need to urgently and how we need to urgently react.
• 15:45
  I think that's something that's really great.
• 15:46
  And so that's the episode.
• 15:48
  This makes me excited because eDNA is fun.
• 15:50
  Collecting ocean information is fun.
• 15:52
  Just as I think about this as I end this episode, the other benefit is you don't
• 15:55
  have to actually have to sample fish.
• 15:56
  This is the stuff that just comes off fish, that comes outta fish or comes
• 16:00
  out of any kind of animal and that we can grab and they can get their DNA.
• 16:02
  It's not as if we're harming them.
• 16:04
  It's not as if the thing.
• 16:05
  It provides a great thing for diversity, which we don't act on enough
• 16:09
  because we don't think we know enough
• 16:10
  about biodiversity.
• 16:12
  We don't know enough about the species and everything like that, or how many species.
• 16:15
  It's really hard to detect, as I mentioned in this podcast.
• 16:17
  So I'd love to hear your thoughts on this method of eDNA.
• 16:20
  If you're a scientist and you've used eDNA before, I would love to hear from you.
• 16:24
  Let me know in the comments below if you're watching this on YouTube.
• 16:27
  And of course, if you want to give me feedback or you want to
• 16:29
  just participate and get into a conversation, I'd love to hear from you.
• 16:33
  You can go to speak up for blue.com/feedback.
• 16:36
  Those of you're listening to audio and you can't comment.
• 16:38
  If you wanna comment on Spotify, you're more than welcome to.
• 16:40
  I'll answer those.
• 16:41
  But also speak up for blue.com/feedback.
• 16:43
  You can leave a voicemail or you can comment.
• 16:46
  I would love to be able to respond to those.
• 16:48
  This is a community, this is what we're building.
• 16:49
  2026 is all about community.
• 16:51
  I've got some really cool things coming.
• 16:53
  I've got a Patreon coming.
• 16:54
  I've got YouTube memberships coming.
• 16:56
  I'm gonna go live a lot more in 2026.
• 16:58
  It's gonna be a lot of fun.
• 16:58
  So stay tuned, subscribe, follow whatever you need to do.
• 17:01
  I love you guys.
• 17:02
  I hope you guys have a great 2026, 'cause I know I'm gonna
• 17:05
  have a great 2026 with this.
• 17:07
  It's gonna be a lot of fun.
• 17:08
  Thank you so much for listening.
• 17:09
  You have been listening to this episode of the How to Protect the ocean Podcast.
• 17:12
  I'm your host Andrew Lewin from the True North Strong and free.
• 17:14
  Have a great day.
• 17:15
  We'll talk to you next time and happy conservation.